1. Field of the Invention
Embodiments of the present invention relate methods, systems, kits and apparatus in the field of medical treatment of patients needing bio-compatible fluids.
More specifically, embodiments of the present invention relate to methods, systems, kits and apparatus for treating patients needing the infusion of bio-compatible fluids, where the apparatus includes an assembly adapted to impart a desired pressure on a container containing a bio-compatible fluid for controlled and/or sustained fluid delivery to the patient.
2. Description of the Related Art
Patients injured by trauma, major surgery, burns, dehydration or hemorrhage, lose body fluid and often need bio-compatible fluids to remain alive. Patients with injuries causing hemorrhaging need volume expanders and blood transfusions; burn victims need electrolyte solutions or plasma protein solutions. The process of supplying the bio-compatible fluids to injured patients is known as “fluid therapy” in which the goal is to “resuscitate” a patient. Fluid therapy is often started by medics in pre-hospital care, but is sustained through care in the emergency department, operating room, and ICU until resuscitation is complete.
Severely injured patients need such fluids in critical amounts and at critical times in varying volumes and administered at various flow rates. The primary purpose of providing fluid is to restore loss of vascular volume (the patient's circulating blood volume). The primary means of administering fluid therapy is to infuse directly into the vascular space via an intravenous catheter or indirectly via an intraosseous catheter or oral intake. Too much fluid or too little fluid (“over-resuscitation” or “under-resuscitation” respectively) can increase patient morbidity and cause death. Further, the optimal rate and timing of providing the bio-compatible fluids varies, depending on the retention and loss of fluid in the vascular volume at different stages of resuscitation. Even further, the optimal volume and rate of fluid provided to the patient depends on the type of the injury such as a brain injury with hemorrhaging or penetrating abdominal injury. An excess or deficiency of total body fluid can occur when the administered fluid is out of balance with fluid losses due to urinary output, gastrointestinal losses, and hemorrhaging.
Typically, emergency personnel as first responders are minimally equipped to measure and determine appropriate amounts and rates of fluid provided to an injured patient. Other critical elements, such as drug delivery, airway maintenance, CPR for heart failure, compression of bleeding tissue, and other acute issues, take priority at the scene or during transit to an emergency room. Thus, emergency personnel often simply add one, two or more bags of fluid to a stand at an elevation higher than the patient and gravity feed the liquid. The volume and rates of fluid delivery are determined by intuition and hopefully experience of the emergency personnel. Fluid infusion rate is crudely controlled with a “thumb wheel” intravenous line occluder valve. In severe trauma, fluid infusion rate is often set “wide open” for rapid restoration of blood volume, but inattentiveness can result in excess fluid delivery. Thus, emergency personnel can easily vary widely from the fluid rate or volume that is optimally needed. It is known that under such circumstances, some patients develop morbidities or even expire due to over-resuscitation or under-resuscitation of the provided fluids. The scenario can be disastrous with a large number of patients suffering trauma such as in a mass transit crash, building collapse, or natural disaster. The limited attention to each patient can cause large discrepancies in the amounts of fluid needed to avoid over-resuscitation or under-resuscitation.
Air or gas pressurized bags can be placed around an intravenous (IV) fluid bag and inflated to a high pressure of typically 300 mm Hg to increase infusion rates when a patient needs a large volume of fluid fast. However, such high rates require even more concentration to monitor and optimally adjust.
An additional problem is the infusion of fluid into the circulation through intraosseous needles. Such intraosseous needles are placed in the bone marrow when veins are difficult to catheterize due to collapsed veins or short and narrow veins in children. The bone marrow provides a virtually uncollapsible vein with access to the circulation, but bone marrow has a low hydraulic conductivity (high resistance), which slows infusion rates. Thus, it would be desirable to have a high pressure infuser system that can deliver fluids from a bag at pressures of 600 mm Hg to 900 mm Hg or higher to achieve sufficient infusion rates when rapid resuscitation is required.
Even if the patient survives to a more fully equipped emergency room, the patient morbidity can increase significantly if the initial and ongoing treatment is inaccurate. One single period of low blood pressure in a patient with head injuries greatly increases that patient's morbidity and mortality. Low blood pressure can occur due to inadequate monitoring and fluid therapy. Fluid therapy for treatment of trauma and hemorrhage are often guided by monitoring a patient's arterial blood pressure, but continuous monitoring of blood pressure and rapid adjustment of infusion rate can be impractical due to other medical tasks required of care givers. This delay of care is exacerbated when multiple patients are present and particularly with mass casualty situations. Further, the data on the volume delivered to the patient can be critical in determining the subsequent fluid therapy.
Timely and accurate monitoring is needed to optimize patient outcomes. The transfer of the patient from the pre-hospital emergency medical team to the hospital emergency department can result in lost or erroneous data concerning the amount and timing of fluid actually delivered to the patient. This missed information can adversely affect the emergency department care-giver's judgment and treatment of the patient. Errors in patient records of fluid therapy can occur due to human errors of measurement and recording. Often fluid volumes infused and urine output produced are measured by visually inspecting IV fluid bags and urinary collection bags. Such an approach can lack accuracy and is intrinsically error prone. An automated system of better monitoring and control of fluid therapy would provide an advantage over the current methods of fluid therapy.
While the emergency room is generally better equipped than a first responder, the technology is still lacking to properly monitor and control the patient's resuscitation. In emergency departments, the volume of total fluid into the patient is typically manually recorded, and there is little data on infusion rates of fluid delivery.
Without displays of the tabular or graphical records of fluid therapy in relationship to clinical endpoints there is a danger of under-resuscitation or over-resuscitation.
Thus, emergency first responders have few tools suitable for the tasks that are critical to survival and generally use intuition and experience in controlling delivery of bio-compatible fluids. The typical large size of equipment and sophisticated controls found in hospitals equipment simply are not appropriate for pre-hospital first responders. These hospital units tend to be heavy and expensive and are relegated to AC power supplies with heavy battery backups. Most pre-hospital care givers do not have access to these units. Even the better equipped emergency rooms and hospitals are limited in the personnel and equipment to handle large scale disasters. Hospitals are also limited in their ability to monitor and optimally control administration of bio-compatible fluids.
Thus, there remains a need in the medical arts for a system, method and apparatus for better monitoring, control, and/or sustained delivery of fluid to a patient in need of bio-compatible fluids, the apparatus being suited for use in hospitals, mobile hospitals, emergency response vehicles, military medical response vehicles and/or field conditions.